Optical engine module

Abstract

An optical engine module including at least two laser sources, collimators, a light combining lens group, an aperture, a beam shaping lens group, a MEMS scanning module, and a beam expansion lens group is provided. The at least two laser sources respectively generate at least two laser beams with different wavelengths. The collimators respectively collimate the at least two laser beams to generate at least two collimated beams. The light combining lens group combines the at least two collimated beams into a combined beam. The aperture filters stray beams of the combined beam. The beam shaping lens group shapes the combined beam to generate a shaped beam with a perfect circle. The MEMS scanning module reflects the shaped beam and scans in horizontal and vertical directions to form a scanning beam. The beam expansion lens group expands the scanning beam into an expanded beam having a predetermined area.

What is claimed is: 
     
       1. An optical engine module, comprising:
 at least two laser sources configured to respectively generate at least two laser beams with different wavelengths; 
 a plurality of collimators for collimating the at least two laser beams to generate at least two collimated beams, respectively; 
 a light combining lens group for combining the at least two collimated beams into a combined beam, wherein the combined beam has a first light shape, and the first light shape is an ellipse having a first length in a first major axis direction and a second length in a first minor axis direction; 
 an aperture having a light hole for filtering out stray beams of the combined beam; 
 a beam shaping lens group for shaping the first light shape of the combined beam along the first minor axis direction to generate a shaped beam having a second light shape, wherein the second light shape is a perfect circle, and the first length is used as a diameter of the perfect circle; 
 a microelectromechanical system (MEMS) scanning module for reflecting the shaped beam and scanning in a horizontal direction and a vertical direction to form a scanning beam; and 
 a beam expansion lens group for expanding the scanning beam into an expanded beam having a predetermined area. 
 
     
     
       2. The optical engine module according to  claim 1 , wherein the beam shaping lens group includes a first concave lens and a first convex lens, the first concave lens is used for receiving the combined beam, the first convex lens is used for outputting the shaped beam, the first concave lens is separated from the first convex lens by a first distance, and the first distance is equal to a focal length of the first convex lens. 
     
     
       3. The optical engine module according to  claim 2 , wherein the beam shaping lens group shapes the combined beam along the first minor axis direction into the second light shape by a magnification factor, the magnification factor is a ratio of the second length to the first length, and the first distance is determined by the magnification factor. 
     
     
       4. The optical engine module according to  claim 2 , wherein the first concave lens has a first focal length, the first convex lens has a second focal length, the first concave lens has a second receiving surface for receiving the combined beam, the first convex lens has a second output surface for outputting the shaped beam, the second receiving surface is separated from the second output surface by a third distance, and the third distance equals the first focal length plus the second focal length;
 wherein the combined beam has a first area, the expanded beam has a second area, and a ratio of the first area to the second area is equal to a ratio of the first focal length to the second focal length. 
 
     
     
       5. The optical engine module according to  claim 1 , wherein the MEMS scanning module includes a vertical mirror and a horizontal mirror, which are respectively used to reflect the shaped beam and scan in the horizontal direction and the vertical direction to form the scanning beam. 
     
     
       6. The optical engine module according to  claim 5 , further comprising a reflector for reflecting the combined beam to the vertical mirror or the horizontal mirror. 
     
     
       7. The optical engine module according to  claim 5 , wherein areas of the vertical mirror and the horizontal mirror are at least larger than an area of the second light shape, and the first distance is further determined by the areas of the vertical mirror and the horizontal mirror. 
     
     
       8. The optical engine module according to  claim 1 , wherein the expanded beam is output to an input coupling zone of a holographic optical element, and the predetermined area corresponds to an area of the input coupling zone. 
     
     
       9. The optical engine module according to  claim 1 , wherein the light hole of the aperture has a third length in a second major axis direction and a fourth length in a second minor axis direction, the second major axis direction is the same as the first major axis direction, and the third length is greater than the first length. 
     
     
       10. The optical engine module according to  claim 1 , wherein the beam expansion lens group includes a plurality of lenses, a number of the plurality of lenses is greater than or equal to two, and the plurality of lenses are selected from a group consisting of a concave lens, a convex lens, a spherical lens and an aspheric lens. 
     
     
       11. The optical engine module according to  claim 10 , wherein the beam expansion lens group includes a second convex lens, a second concave lens, a third convex lens, and a fourth convex lens arranged in sequence along an optical axis, and wherein the second convex lens has a first receiving surface for receiving the scanning beam, and the fourth convex lens has a first output surface for outputting the expanded beam. 
     
     
       12. The optical engine module according to  claim 11 , wherein the first receiving surface and the first output surface are separated by a second distance, and the second distance is inversely proportional to a scanning angle of the MEMS scanning module, and wherein the scanning angle is an angular variation range of an exit angle at which the scanning beam is output from the MEMS scanning module. 
     
     
       13. The optical engine module according to  claim 1 , further comprising a light detector, wherein the light combining lens group combines the at least two collimated beams into the combined beam and outputs the combined beam in a combined light direction, and the light combining lens group further outputs a portion of the combined beam to the light detector in a light splitting direction.